Method of producing jack sinkers for straight bar knitting machines



Sept. 16, 1941. e. H. GREEN 2,256,428

METHOD OF PRODUCING JACK SINKERS FOR STRAIGHT BAR KNITTING MACHINESFiled April 8, 1940 F166. FIG. 7.

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//7 Venar Patented Sept. 16, 1941 STRAIGHT BAR KNITTING CHINES IVIA-George Henry Green, Leicester, England Application April 8, 1940, SerialNo. 328.540

7 In Great Britain April 3, 1939 3 Claims.

This invention comprises an improved method of producing jack sinkersfor straight bar knitting machine and also results in the production ofa jack sinker of novel construction. The principal object of theinvention is to provide a method of producing a jack sinker as aboveequal in strength and quality to sinkers of this type as hithertoproduced, which is much simpler and considerably cheaper than previouslyknown methods.

Hitherto jack sinkers as above have comprised a central blade member andtwo side portions which have been fixed to the central blade, usuallyone on each side thereof, at the rear end of the blade, by riveting orwelding the side pieces and central blade together. The central bladehas been provided with an upwardly projecting rectangular butt at itsrear end and this butt has been strengthened or reinforced by the saidtwo side pieces. By virtue of the central blade member having theintegral upwardly projecting butt at its rear end it has hitherto beennecessary to stamp the said central blade from a strip of material equalin width at least to the distance from the lower edge of the blade tothe top edge of the butt and in fact it has been customary in stampingout the said blade to employ a punch and die equal in size and shape tothe complete sinker blade. This process has necessitated the use ofcomparatively large and expensive'punches and dies and as the sinkerblade material is extremely hard it is frequently necessary to replacethese expensive tools. Furthermore the provision of the projecting button the central blade has rendered the subsequent finishing oi the bladeto the extremely accurate limits which are essential for the sinkerrather difficult and expensive.

The improved method provided by this invention consists in manufacturingthe main blade member of the sinker from a parallel strip of material ofthe same width as the width of the said blade, or of a width which isonly slightly larger to allow for it being ground to the exact widthrequired for the said blade, parting the said strip into lengths equalto the overall length of the said sinker, forming one end of each lengthwith the customary neb, throat and nose of a sinker and securing at theopposite end of the said blade a separate part adapted to serve as anoperating butt for the sinker.

By the above method a jack sinker for a straight-bar knitting machine isproduced embodying a main blade member which has no integral abutmentprojecting from either of its longitudinal edges and in which the buttfor enabling the sinker to be moved in its operation in the machine iscomprised solely by one or more side pieces secured to the said blademember.

For the purpose of clearly describing the improved process and articleaccording to this inyen-tion reference will now be made tothemcompanying drawing wherein:

Fig. 1 is a plan'viewof a supply of the material from which the jacksinker blades are to be formed.

Fig. 2 illustrates a grinding operation on said material.

Fig. 3 illustrates a stamping operation on the said material and a means.for accurately positioning same.

Fig. 4 isa perspective view of the separate parts of the jack sinker.

Fig. 5 is a side elevation of the finishedsinker.

Figs. '6 and 7 are end elevations of two alter-. native constructions ofthe sinker.

The blade member of a jack sinker as above can be very cheaplymanufactured in the following manner: The sinker blade material I may bepurchased in coiled strip form, conveniently annular in shape, see Fig.'1,' and the width of the strip should be very slightly larger than thefinished width of the sinker blade B. The material in this form may berigidly supported by'an inner and outer metal ring 2 and 2a, the outermetal ring 2 being provided with suitable means, such as a screwedspindle 3 and nuts 4, for enabling it to be contracted and tightenedaround the outer face of the annular supply of coiled strip metal I andthe inner ring Zabeing provided with means, such as the oppositelythreaded screw spindle 30. for enabling it to be expanded and tightenedaround the inner surface of the said annular supply of material. Thusrigidly supported-the two metal supporting rings being of smaller widththan the width of the material, see Fig. 2, the annular supply of stripmaterial is put on to the magnetized table 5 of a surface grindingmachine and the two edges BI and B2 of the coiled strip l are grounddead to s'izeby the one or more grinding wheels 6. These two edgesrepresent the finished upper and lower horizontal edges of thesinkerblade B and the extremely accurate dead parallel width of the sinkerblade is thereby assured by this one simple grinding operation. 7

The supporting rings 2 and 2a are then re-, moved from the annularsupply of strip material I and the material is fed into a press providedwith punch and die, shaped according to the shaded portion shewn in Fig.3 which is one operation shapes the front edge B3 of the sinker, i. e.,provides the said front edge with the customary neb, throat and nose ofa sinker, and provides the rear straight vertical edge B4 of thepreceding sinker blade. In order to assure the accurate positioning ofthe throat B4 of the sinker in relation to the longitudinal edges BI andB2 of the sinker blade B means are preferably provided in the press forpressing either the upper or lower longitudinal edge of the bladeagainst an accurately positioned abutment. Such positioning means mayconveniently incorporate spring pressed members 1 which automaticallyhold the.

upper longitudinal edge B of the sinker blade B against the abutment 8.The manufacture of the sinker blade is thus complete except for theusual rumbling and polishing operations.

Substantially L-shaped side pieces S, see Figs. 4 and 5, are thensecured to the sinker blade as above, one on each side thereof, at therear end of the said blade and these side pieces are convenientlysecured to the said blade by a welding process in accordance with my U.S. A. Patent No. 2,179,888, patented Nov. 14, 1939, at the positionsindicated at SI. The said side pieces may, however, if desired, be'secured to the said blade by riveting the said side pieces. andbladetogether at the positions SI, in the well known manner, and one sidepiece only may be provided if so desired. When secured in position onthe sinker blade the one or two side pieces S provide the usualrectangular shaped butt or abutment A, Fig. 5, projecting upwardly fromthe upper longitudinal edge of the sinker blade at the rear end thereofand it is by means of this butt that the sinker is moved by thecatch-bar and jack during its operation in the machine.

Conveniently each of the abutment pieces S may be made with twothicknesses, which may be provided by a grinding operation, see Figs. 4and 6, so that when the upper parts of said pieces are placed face toface thereis a space between their lower partsto accommodate" the sinkerblade B and the entire outer side faces of the side pieces, a

when the sinker is assembled, are parallel.

Alternatively, see Fig. '7, the upper part of each of the side pieces Swhich part projects upwardly from the sinker may be cranked inwardly tothe extent of half the thickness of the sinker eration described withreference to Fig. 2 could be dispensed with.

By virtue of welding the side pieces S directly together at their upperparts and through the sinker blade B in accordance with my U. S. PatentNo. 2,179,888 at their lower horizontal parts,

see Fig. 5, a particularly strong and durable construction of jacksinkers is provided.

I claim:

1. The method of producing jack sinkers for knitting machines, whichcomprises edge-grinding an elongated strip of blade-making material tobring its edges into parallelism throughout its length and to produce awidth substantially equal to that of the finished blade; cuttingpredetermined lengths from said strip to constitute blade elements, bysuccessively severing the strip transversely from edge to edge, whilesimultaneously therewith shaping one end portion of one of the elementsto form the sinker nose, throat and neb; and securing to the oppositeend portion of each severed element a butt piece having a portionextending transversely beyond one edge of said element.

2. The method of making jack sinkers for knitting machines, whichcomprises providing a roll of blade-forming strip material; grinding theopposite fiat faces of said roll to bring the edges of said stripmaterial into parallelism and reduce its width to substantially that ofthefinished blade; cutting successive predetermined lengths from saidstrip to constitute blade elements, by severing the strip transverselyfrom edge to edge, thereby forming a butt edge on one element, andsimultaneously therewith shaping an end portion of the adjacent elementto form the sinker nose, throat and neb; and securing an offset buttpiece to the butt portion of each element.

3. The method of making jack sinkers for knitting machines, Whichcomprises providing a strip of blade-making material of uniform widththroughout its length, which width is substantially equal to that of thefinished blade; severing said strip from edge to edge at longitudinallyspaced points to form imperforate blade elements of uniform widththroughout their length, said severances each producing a transversebutt edge on one blade element which is perpendicular to thelongitudinal edges thereof, and simultaneously therewith. shaping an endportion of an adjacent blade element to form the sinker nose, throat andneb; and securing an offset buttpiece to the butt end portion of thesevered elements.

GEO/RGE HENRY GREEN.

